We get back to proving the First Incompleteness Theorem next week. In this week’s five chapters, we are reading into the record some necessary arithmetical background. Everything in today’s chapter will very probably be quite familiar; but we do need to say just a little in GWT (a very little) about  ‘First-order Peano Arithmetic’, the benchmark formalized theory of arithmetic.  The most interesting claims (for a student who has not met them before, unlikely for a reader of this blog!) are those in the final section about non-standard models — but that brisk section is optional! The post Gödel Without Tears, slowly, 6 appeared first on Logic Matters.